Depth Perception Flashcards
binocular disparity
the differences between your two retinal images for the same scene
binocular summation
combining the two eyes’ signals allows inferences that aren’t possible with one
allows for stereopsis
stereopsis
perception of depth calculated via multiple view points (i.e. 2 eyes)
monocular vs. binocular
mono - 1 eye
bi - 2 eyes
depth cues
information in environment that tells you how distance is being tracked
monocular depth cues
occlusion
- relative cue of order
relative size/height
- smaller items must be further away
- higher objects are further
texture gradients
- at further distances, textures become smaller, tighter and their spatial frequency increases
aerial perspective
- brain understands that light scatters as it moves through our atmosphere
- further away = hazy
linear perspective
- lines that are // in the 3D world will appear to converge as they extend away from POV, aka vanishing point
motion parallax
- objects closer to you will pass by more quickly than objects further away
monocular cues rely on previous knowledge, aka …
familiar size
- we use object knowledge to make assumptions about depth
ex) hand that is big is closer to us, not just a big hand
If an object’s color is becoming less vivid, and more
white (not more black), it is changing in what factor?
a) Hue
b) Saturation
c) Brightness
d) Opponency
B
why do many species have 2 eyes?
triangulation
- can figure out the relative distance of an item by knowing a distance between 2 points (your eyes) and the angles at which the item is to those 2 points
if you know 2 angles of a triangle you can figure out 3rd one
convergence in eye position
turning inward for near objects
divergence in eye position
turning outward for far objects
corresponding retinal point
seeing one image of object with 2 eyes/retina images
Horopter (Vieth-Muller circle)
anything on this ring in your retinal image will not have binocular disparity
Stereopsis Zone/Panum’s Fusion Area
zone along the Horopter ring
if object is in this zone but not along ring, it will have a small enough disparity that your brain can overrule it to allow you to see one object with 2 eyes
diplopia
double vision caused by disparity past the Panum’s Fusion Area
disparity types
crossed = object is closer than fixation
uncrossed = object is further than fixation
stereoacuity
the smallest degree of difference in binocular disparity that can generate a sensation of depth
free fusion
you can actively cross or uncross your vision to produce 3D images in stereographic images
dichoptic
2 eyes getting different inputs
what original 3D movies relied on to transmit different information to each eye
correspondence problem
the brain trying to figure out how things match up when 1 retina is receiving different information than the other
also when you can only see certain things in one eye but not the other (slide 47)
binocular rivalry
when two eyes are getting different inputs, can compete for visual dominance
3 things that affect correspondence problem
spatial frequency
- lower spatial frequency information is generally easier to achieve correspondence (fewer fine details to match)
uniqueness
- any given feature should be represented exactly 1 time in each retinal image
continuity
- neighboring points (except at edges of objects) should be at similar distances
evidence that some cells code for _____ while others code for ____
correspondence; disparity
where is the first place that cells respond to both eyes?
V1
stereoblindness
inability to make use of binocular disparity as a depth cue
can result from childhood visual disorder
most people who are stereoblind don’t realize it
strabismus
two eyes are misaligned and brain doesn’t account for this difference
one eye has the object reflected on the fovea while the other eye has the image reflected on a nonfoveal area
esotropia vs. exotropia in strabismus
eso - eye deviates inward
exo - eye deviates outward
which of these woild not provide depth information to a person with only one eye?
motion parallax
aerial perspective
dichoptic viewing
relative height
dichoptic viewing
Pia is staring at a dog in the distance. There is also a cat closer to her than where she is fixated. What is true about her vision of the cat if she doesn’t moved her fixation, assuming the cat is not within Panum’s Fusion Area?
the cat will be seen with crossed disparity
the cat will be seen with uncrossed disparity
the cat will be seen with stereopsis
the cat won’t be seen at all
the cat will be seen with crossed disparity
